According to the California Department of Food and Agriculture, 45,341 acres of vineyards are planted in Napa, 59,509 acres in Sonoma. Together, the counties employ more than 100,000 workers. Combining recent estimates from the Sonoma County Winegrowers and the Napa Valley Vintners, the wine industry in both counties is worth more than $27 billion to local economies.

The city of Calistoga in Napa County was the latest area to receive a mandatory evacuation and advisory order because of the 17 wildfires raging through wine country as wineries began to assess their damage.

How many wineries and vineyards have burned?

Unknown. On Wednesday morning, the Sonoma County Winegrowers stated that it has “been unable to obtain accurate updates from Sonoma Valley as most of that area is still under evacuation orders.” The fires continue to spread, affecting vineyards in Mendocino and Solano counties as well. For the latest list of wineries that have sustained damage, click here.

What proportion of the grapes has already been harvested?

Late summer and early fall is harvest season for the wine industry. In terms of the amount of grapes that has already been harvested, before the fires, estimates from individual winemakers have ranged from 75 percent to 95 percent, though most agree the average is 90 percent. The heat spike that hit Northern California in early September sped up the harvest. White wine grapes are completely in, as are most grapes used to produce lighter reds. The grapes remaining on the vines are primarily from late-harvest varieties such as Cabernet Sauvignon and Syrah.

Will the fires’ smoke affect the wines?

Winemakers do not appear to be concerned about smoke taint on the grapes, primarily because the unpicked grapes are so mature. However, smoke may affect the many wines that are currently undergoing fermentation. “Fermentation produces carbon dioxide, so it needs to be vented — you can’t have a tank be completely sealed,” said Sarah Green, assistant winemaker at Fel Wines. The process that can take from a few days to several weeks. “It’s not entirely clear how the smoke is interacting with the grapes in the tanks.”